There are 12 paired ribs, 7 or 8 of which are true ribs and articulate directly with the sternum. The first rib articulates with the T1 vertebra only and does not contact C7. The remaining true ribs articulate with their corresponding vertebra and the one above. False ribs articulate with the costal cartilages and the vertebra. The two floating ribs articulate only with their vertebral bodies. The parietal and visceral pleura have separate embryologic origins, including vascular, lymphatic, and neural supply. The sternum has three separate but connected divisions, the manubrium, body, and xiphoid. By the start of the fifth decade, the xiphoid has usually ossified and united with the body of the sternum so it is no longer a three-part construct. The neurovascular bundles are found between the internal and innermost intercostals (not the external and internal). They are arranged as vein, artery, and nerve in descending order and are generally well protected at the inferior aspect of each rib.1 The internal mammary artery arises from the first part of the subclavian artery passing 1 cm lateral to the sternum. The internal mammary vessels are highly relevant to chest wall reconstruction because they supply commonly used flaps such as the rectus abdominus and pectoralis major muscles. Furthermore, they may be sacrificed during cardiac procedures such as coronary bypass grafting or major chest wall resections. The internal mammary vessels are also relevant to free tissue transfer to the chest wall such as for anastomoses in breast reconstruction. Knowledge of their anatomy is therefore important. When using these vessels for free tissue transfer, the third intercostal space or higher is often used for access, because the veins get progressively smaller distally and usually bifurcate at or distal to this point. The veins and artery are usually a good caliber at this level.2
2. Clark CP III, Rohrich RJ, Copit S, Pittman CE, Robinson J. An anatomic study of the internal mammary veins: clinical implications for free-tissue-transfer breast reconstruction. Plast Reconstr Surg 1997;99(2):400–404 Muscles involved in respiration can be classified in three groups, primary, secondary, and accessory (used in times of respiratory distress).1 Primary muscles are the diaphragm and intercostals (external, internal, and innermost), which are supplied by the phrenic nerve and intercostal nerves, respectively. The intercostal nerves are formed by the anterior divisions of the T1–T11 thoracic nerves. Secondary muscles of respiration are the sternocleidomastoid, serratus posterior, scalenes (anterior, middle, and posterior) and levatores costarum. The innervations of these muscles are the spinal accessory for the sternocleidomastoid, T9–T12 intercostal nerves for the serratus posterior, C4–C6 for the scalenes, and the lateral divisions of the posterior primary rami of the corresponding spinal nerves for the levatores costarum. Accessory muscles of respiration include the serratus anterior, supplied by the long thoracic nerve (C5–C7), and the pectoralis major, supplied by medial and lateral pectoral nerves (C5–C7 and C8, T1, respectively).1,2
Decisions regarding reconstruction of the thoracic skeleton will be made on an individual patient basis depending on baseline respiratory function and the impact of the defect on respiratory function; however, the usual guidelines for reconstruction of the thoracic skeleton are: 1. Defects where four contiguous ribs have been removed 2. Defects larger than 5 cm in diameter But these indications will differ as follows: 1. Previous radiation treatment stiffens the chest wall so larger defects may be tolerated without reconstruction. 2. Posterior defects are better tolerated without reconstruction given the support of the bony scapula and musculature. 3. Patients with poor respiratory reserve such as chronic obstructive pulmonary disease (COPD) will tolerate defects less well and may benefit from reconstruction of smaller defects. Sternal defects can be classified by using either the Pairolero and Arnold1 or Starzynski et al2 classifications. These are significantly different to one another, although each has the same number of grades/types. The Starzynski classification is based on the anatomic structures missing, as well as the physiological deficit incurred. The Pairolero classification is based on chronicity and the presence or absence of infection. The omental flap is a useful option for chest wall reconstruction and receives blood supply from the gastroepiploic vessels, not the superior epigastric vessels. The Eloesser flap is an inferiorly based U-shaped flap from the posterior chest wall that is turned into the thoracic cavity to facilitate passive drainage of empyema. It does not address bronchopleural fistula. Thoracoplasty treats both bronchopleural fistula and empyema in a single surgery, but results in rib cage deformity and interferes with upper limb function.
Pairolero and Arnold1 described a classification for sternotomy wounds in 1986. The classification is based on the timing of the defect relative to surgery (early, intermediate, or late) and the presence or absence of active infection as evidenced by cellulitis, positive swabs, or osteomyelitis. They described treatment according to the subtype as follows: • Type 1: – Serosanguineous drainage within the first 3 days of surgery – No active infection – Treatment: Re-exploration, debridement, and closure of the defect directly • Type 2: – Purulent discharge within the first 3 weeks of surgery – Active infection evident – Treatment: Exploration, debridement, and coverage of the defect with a soft tissue flap • Type 3: – Chronically infected wound months or years after surgery The other factors listed do not form part of the Pairolero description. This classification system is often discussed in the setting of clinical viva scenarios in plastic surgery.
This patient probably requires reconstruction with a right vertical rectus abdominis myocutaneous flap. This is the most appropriate option because it provides good soft tissue cover, is able to fill the dead space, and provides robust skin to close the wound directly. Although infection is no longer present, importation of well-vascularized muscle into such defects is preferable. The internal mammary vessels supplying the flap are intact, whereas they are not on the other side. The defect is probably too low for a left pectoralis major advancement and a turnover flap should be avoided anyway due to harvest of the internal mammary artery on this side. Given the diagnosis of Poland’s syndrome the sternal head of the muscle is not available for harvest on the right-hand side. Alternative options not listed may include an omental pedicled flap but would require a skin graft and the abdominal cavity would have to be opened. A left latissimus dorsi myocutaneous flap could be used. A disadvantage would be a need to turn the patient intraoperatively. Achieving adequate reach is possible in these scenarios, but normally requires detachment at the humeral insertion and division of the thoracodorsal nerve to stop muscle contractions.1–3 The rectus abdominis is normally reserved for patients with an intact superior vascular supply. However, rectus muscle advancement for sternal wound reconstruction has been described using the deep inferior epigastric system and releasing the other fascial and tendinous attachments to provide a 12 cm advancement.4
by 4 cm defect over the left upper third of his sternum, with sternal loss and exposed mediastinum. The right This patient has a proximal left-sided defect that is relatively small, and the contralateral internal mammary is preserved. Therefore, a right pectoralis major turnover flap combined with a split-skin graft is a suitable option. A pedicled ipsilateral latissimus dorsi is usually an option if reach is sufficient. However, neither this nor the serratus flap will be available on the ipsilateral side in this patient because of the previous thoracotomy. A free flap could be used with anastomoses into the right internal mammary vessels, but this would be unnecessary in a complex patient where the simpler and reliable alternative of a pectoralis major flap was an option. The vertical rectus flap is more usually reserved for long and inferior sternal defects and, in this case, we have no information to suggest the left internal mammary vessels are intact, so it is best avoided.1,2
This patient has no remaining local muscle flap options to reconstruct a defect of this size. In this case, an omental flap would represent the best choice from the options listed. Omental flaps are traditionally used more often than free tissue transfers to reconstruct extensive chest wall defects. If a free muscle transfer was used in this case, a free contralateral latissimus dorsi, or a free anterolateral thigh (ALT) or deep inferior epigastric perforator (DIEP) would also be reasonable choices. She is not a good candidate for reconstruction with a right vertical rectus flap because of the previous cholecystectomy incision.1–3
Poland’s syndrome is a congenital condition in which there are a number of upper limb and chest wall abnormalities. It occurs in approximately 1:30,000 births and affects males and females equally. The right side is affected more often than the left side by a ratio of 2:1. It is postulated that the subclavian vessels are compressed in the first (not second) trimester. A consistent finding is the absence of the sternal head (not the clavicular head) of the pectoralis major. Although rare, Poland’s syndrome can be associated with Möbius syndrome and therefore with the absence of cranial nerves VI and VII. Patients with Poland’s syndrome are often seen by plastic surgeons with regard to reconstruction of both the upper limb and chest/breast deformities. Sometimes the latissimus dorsi muscle is transferred to the anterior chest wall to reconstruct the pectoralis deficiency. This is particularly useful in female patients to provide a foundation for future breast reconstruction using implant-based techniques.1–4
Poland’s syndrome represents a spectrum of abnormalities affecting the ipsilateral chest wall and upper limb. Common key findings include the following: • Absence of the sternal head of the pectoralis major • Absence of costal cartilages • Hypoplasia of breast tissue, including the nipple-areola complex • Deficiency of subcutaneous fat and axillary hair • Syndactyly or hypoplasia of the ipsilateral extremity Additional features that occur less commonly include the following: • Absence of the pectoralis minor • Shortening of the forearm • Deformity of chest wall muscles, including the serratus, latissimus dorsi, and external oblique • Total absence of anterolateral ribs with herniation of the lung • Associations with Möbius syndrome • Symphalangism Common surgical procedures for the chest in Poland’s patients include latissimus dorsi transfer to reconstruct the pectoralis major deficiency, and breast reconstruction with a variety of implant of autologous techniques. Surgery for the limb may include syndactyly release and, occasionally, free toe-to-hand transfer.1–4
Pectus excavatum is the most common chest wall deformity affecting 1 in 400 children and affects males more than females with a ratio of 4:1. It occurs 10 times more frequently than pectus carinatum and is called funnel chest, not pigeon chest. (Pigeon chest refers to pectus carinatum.) Funnel chest occurs secondary to excess growth of the lower costal cartilages resulting in a sternal depression. The sternum will rotate if growth is greater on one side. The condition becomes progressively worse with time and continued growth, leaving a cosmetic and sometimes functional deformity. It is treated surgically relatively early (2–5 years of age is recommended) using Nuss procedure, sternal turnover, or sternal osteotomies. A key motivation for patients to consider surgery is the aesthetics of the deformity. Surgery with the Nuss procedure involves a minimally invasive approach that slips concave steel bars behind the sternum through two small incisions. The bar is flipped to a convex position to anteriorly displace the sternum and correct the deformity.1–4
Pectus carinatum (pigeon chest) is characterized by anterior protrusion of the sternum but rarely causes physiologic symptoms. It affects males more than females (4:1 ratio), and a positive family history is present in a third of cases. Three subtypes are recognized: chondrogladiolar (most common), pouter pigeon chest, and lateral depression of the ribs. The latter is commonly associated with Poland’s syndrome. Pouter pigeon chest is least common and involves protrusion of the manubrium and depression of the sternal body. Chondrogladiolar is most common and involves anterior displacement of the sternal body and symmetrical concavity of costal cartilages. Several surgical options are available, including repositioning of the sternum, excision of costal cartilages, and the use of strut techniques such as the Ravitch procedure. This technique is, however, not absolutely required and is not totally specific to pectus carinatum.1–3